/*
 * Copyright (C) 2010 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.hapjs.features.barcode.camera;

import android.content.Context;
import android.graphics.Point;
import android.hardware.Camera;
import android.util.Log;
import android.view.Display;
import android.view.WindowManager;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;

/**
 * A class which deals with reading, parsing, and setting the camera parameters which are used to
 * configure the camera hardware.
 */
final class CameraConfigurationManager {

    private static final String TAG = "CameraConfiguration";

    // This is bigger than the size of a small screen, which is still supported. The routine
    // below will still select the default (presumably 320x240) size for these. This prevents
    // accidental selection of very low resolution on some devices.
    private static final int MIN_PREVIEW_PIXELS = 480 * 320; // normal screen

    // private static final float MAX_EXPOSURE_COMPENSATION = 1.5f;
    // private static final float MIN_EXPOSURE_COMPENSATION = 0.0f;
    private static final double MAX_ASPECT_DISTORTION = 0.15;

    private final Context context;
    private Point screenResolution;
    private Point cameraResolution;

    CameraConfigurationManager(Context context) {
        this.context = context;
    }

    private static String findSettableValue(
            Collection<String> supportedValues, String... desiredValues) {
        Log.i(TAG, "Supported values: " + supportedValues);
        String result = null;
        if (supportedValues != null) {
            for (String desiredValue : desiredValues) {
                if (supportedValues.contains(desiredValue)) {
                    result = desiredValue;
                    break;
                }
            }
        }
        Log.i(TAG, "Settable value: " + result);
        return result;
    }

    /**
     * Reads, one time, values from the camera that are needed by the app.
     */
    void initFromCameraParameters(Camera camera) {
        Camera.Parameters parameters = camera.getParameters();
        WindowManager manager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
        Display display = manager.getDefaultDisplay();
        Point theScreenResolution = new Point();
        display.getSize(theScreenResolution);
        screenResolution = theScreenResolution;
        Log.i(TAG, "Screen resolution: " + screenResolution);
        cameraResolution = findBestPreviewSizeValue(parameters, screenResolution);
        Log.i(TAG, "Camera resolution: " + cameraResolution);
    }

    void setDesiredCameraParameters(Camera camera, boolean safeMode) {
        // modify
        camera.setDisplayOrientation(90);
        Camera.Parameters parameters = camera.getParameters();
        if (parameters == null) {
            Log.w(
                    TAG,
                    "Device error: no camera parameters are available. Proceeding without configuration.");
            return;
        }
        Log.i(TAG, "Initial camera parameters: " + parameters.flatten());
        if (safeMode) {
            Log.w(TAG, "In camera config safe mode -- most settings will not be honored");
        }
        String focusMode =
                findSettableValue(parameters.getSupportedFocusModes(),
                        Camera.Parameters.FOCUS_MODE_AUTO);
        // Maybe selected auto-focus but not available, so fall through here:
        if (!safeMode && focusMode == null) {
            focusMode =
                    findSettableValue(
                            parameters.getSupportedFocusModes(),
                            Camera.Parameters.FOCUS_MODE_MACRO,
                            Camera.Parameters.FOCUS_MODE_EDOF);
        }
        if (focusMode != null) {
            parameters.setFocusMode(focusMode);
        }
        parameters.setPreviewSize(cameraResolution.x, cameraResolution.y);
        camera.setParameters(parameters);
        Camera.Parameters afterParameters = camera.getParameters();
        Camera.Size afterSize = afterParameters.getPreviewSize();
        if (afterSize != null
                &&
                (cameraResolution.x != afterSize.width || cameraResolution.y != afterSize.height)) {
            Log.w(
                    TAG,
                    "Camera said it supported preview size "
                            + cameraResolution.x
                            + 'x'
                            + cameraResolution.y
                            + ", but after setting it, preview size is "
                            + afterSize.width
                            + 'x'
                            + afterSize.height);
            cameraResolution.x = afterSize.width;
            cameraResolution.y = afterSize.height;
        }
    }

    Point getCameraResolution() {
        return cameraResolution;
    }

    Point getScreenResolution() {
        return screenResolution;
    }

    boolean getTorchState(Camera camera) {
        if (camera != null) {
            Camera.Parameters parameters = camera.getParameters();
            if (parameters != null) {
                String flashMode = camera.getParameters().getFlashMode();
                return flashMode != null
                        && (Camera.Parameters.FLASH_MODE_ON.equals(flashMode)
                        || Camera.Parameters.FLASH_MODE_TORCH.equals(flashMode));
            }
        }
        return false;
    }

    void setTorch(Camera camera, boolean newSetting) {
        Camera.Parameters parameters = camera.getParameters();
        doSetTorch(parameters, newSetting, false);
        camera.setParameters(parameters);
    }

    private void doSetTorch(Camera.Parameters parameters, boolean newSetting, boolean safeMode) {
        String flashMode;
        if (newSetting) {
            flashMode =
                    findSettableValue(
                            parameters.getSupportedFlashModes(),
                            Camera.Parameters.FLASH_MODE_TORCH,
                            Camera.Parameters.FLASH_MODE_ON);
        } else {
            flashMode =
                    findSettableValue(parameters.getSupportedFlashModes(),
                            Camera.Parameters.FLASH_MODE_OFF);
        }
        if (flashMode != null) {
            parameters.setFlashMode(flashMode);
        }

        /*
        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
        if (!prefs.getBoolean(PreferencesActivity.KEY_DISABLE_EXPOSURE, false)) {
          if (!safeMode) {
            int minExposure = parameters.getMinExposureCompensation();
            int maxExposure = parameters.getMaxExposureCompensation();
            if (minExposure != 0 || maxExposure != 0) {
              float step = parameters.getExposureCompensationStep();
              int desiredCompensation;
              if (newSetting) {
                // Light on; set low exposue compensation
                desiredCompensation = Math.max((int) (MIN_EXPOSURE_COMPENSATION / step), minExposure);
              } else {
                // Light off; set high compensation
                desiredCompensation = Math.min((int) (MAX_EXPOSURE_COMPENSATION / step), maxExposure);
              }
              Log.i(TAG, "Setting exposure compensation to " + desiredCompensation + " / " + (step * desiredCompensation));
              parameters.setExposureCompensation(desiredCompensation);
            } else {
              Log.i(TAG, "Camera does not support exposure compensation");
            }
          }
        }
        */
    }

    private Point findBestPreviewSizeValue(Camera.Parameters parameters, Point screenResolution) {
        List<Camera.Size> rawSupportedSizes = parameters.getSupportedPreviewSizes();
        if (rawSupportedSizes == null) {
            Log.w(TAG, "Device returned no supported preview sizes; using default");
            Camera.Size defaultSize = parameters.getPreviewSize();
            return new Point(
                    defaultSize != null ? defaultSize.width : 0,
                    defaultSize != null ? defaultSize.height : 0);
        }
        // Sort by size, descending
        List<Camera.Size> supportedPreviewSizes = new ArrayList<>(rawSupportedSizes);
        Collections.sort(
                supportedPreviewSizes,
                new Comparator<Camera.Size>() {
                    @Override
                    public int compare(Camera.Size a, Camera.Size b) {
                        int aPixels = a.height * a.width;
                        int bPixels = b.height * b.width;
                        if (bPixels < aPixels) {
                            return -1;
                        }
                        if (bPixels > aPixels) {
                            return 1;
                        }
                        return 0;
                    }
                });
        if (Log.isLoggable(TAG, Log.INFO)) {
            StringBuilder previewSizesString = new StringBuilder();
            for (Camera.Size supportedPreviewSize : supportedPreviewSizes) {
                previewSizesString
                        .append(supportedPreviewSize.width)
                        .append('x')
                        .append(supportedPreviewSize.height)
                        .append(' ');
            }
            Log.i(TAG, "Supported preview sizes: " + previewSizesString);
        }
        double screenAspectRatio = (double) screenResolution.x / (double) screenResolution.y;
        // Remove sizes that are unsuitable
        Iterator<Camera.Size> it = supportedPreviewSizes.iterator();
        while (it.hasNext()) {
            Camera.Size supportedPreviewSize = it.next();
            int realWidth = supportedPreviewSize.width;
            int realHeight = supportedPreviewSize.height;
            if (realWidth * realHeight < MIN_PREVIEW_PIXELS) {
                it.remove();
                continue;
            }
            boolean isCandidatePortrait = realWidth < realHeight;
            int maybeFlippedWidth = isCandidatePortrait ? realHeight : realWidth;
            int maybeFlippedHeight = isCandidatePortrait ? realWidth : realHeight;
            double aspectRatio = (double) maybeFlippedWidth / (double) maybeFlippedHeight;
            double distortion = Math.abs(aspectRatio - screenAspectRatio);
            if (distortion > MAX_ASPECT_DISTORTION) {
                it.remove();
                continue;
            }
            if (maybeFlippedWidth == screenResolution.x
                    && maybeFlippedHeight == screenResolution.y) {
                Point exactPoint = new Point(realWidth, realHeight);
                Log.i(TAG, "Found preview size exactly matching screen size: " + exactPoint);
                return exactPoint;
            }
        }
        // If no exact match, use largest preview size. This was not a great idea on older devices
        // because
        // of the additional computation needed. We're likely to get here on newer Android 4+ devices,
        // where
        // the CPU is much more powerful.
        if (!supportedPreviewSizes.isEmpty()) {
            Camera.Size largestPreview = supportedPreviewSizes.get(0);
            Point largestSize = new Point(largestPreview.width, largestPreview.height);
            Log.i(TAG, "Using largest suitable preview size: " + largestSize);
            return largestSize;
        }
        // If there is nothing at all suitable, return current preview size
        Camera.Size defaultPreview = parameters.getPreviewSize();
        if (defaultPreview == null) {
            Log.i(TAG, "defaultPreview is null, return screenResolution default ");
            return new Point(0, 0);
        }
        Point defaultSize = new Point(defaultPreview.width, defaultPreview.height);
        Log.i(TAG, "No suitable preview sizes, using default: " + defaultSize);
        return defaultSize;
    }
}
